Nonautomated appraisals from very experienced domainers can be useful.
Though in the end it's the waiting game, personal experience & knowledge and how much the buyer is willing to pay for the particular domain.
Comparable sales are lacking, one can't base the domain's value only on comparable sales.
There will always be more sales and statistics will change.
There can be a rich buyer who all of a sudden really likes a specific domain while the domain's owner is a domain investor who usually "overprice" his domains

The rich buyer may not care at all or even know that the domain is overpriced and buy it outright.
A corporation won't care if it is 5 or 7 figures or even 8 figures.
Voice.com $30M sale is the latest example.
No appraisal tool would have appraised Voice.com at 8 figures before this sale because there was simply not enough data to support such a price.
I imagine that 99% of domainers wouldn't dream of such a sale price for this particular domain.
If someone asked me to appraise it, I would have appraised this domain at low 7 figures and maybe if pushing it mid 7 figures End user(based on similar sales and the domain's potential).
The same goes for the early 7 figures domain sales in the late 90's and early 2000's.
There were no appraisal tools or established market prices in the beginning, only guesses of some "get rich quick" sums of money.